This invention relates generally to the field of internal combustion engines and more particularly to a two piece valve cover using a combination of thin and thick gauge materials.
Since the development of the internal combustion engine, there has been a need to cover to seal the valve train from the external environment so as to prevent contamination of the engine and the loss of engine oil. This cover has to be removed occasionally to gain access to the valve train for inspection and/or repair.
Valve covers when formed accomplish two basic functions, one is to act as a cover for the valve train and the other is to have a method of attaching the cover to the cylinder head. Prior technology has only allowed the cover and attaching flange to be formed from the same material as the cover.
Prior technology uses a one piece cover, which can be made by stamping or casting methods well known to the industry with material suitable to be cast or formed in a rigid form suitable for use on an internal combustion engine. Such cover products are then fastened to the cylinder head of the internal combustion engine containing the valve train components along with a gasket material placed between the valve cover flange and cylinder head gasket rail. Prior technology only allowed cast covers to be formed as a two piece unit because of the critical dimensions needed to match top and bottom portions of the valve cover. This two part design has its advantages in some situation, such as racing to help reduce down time.
However, all of the prior valve cover manufacturing methods have their deficiencies. One piece covers that are stamped from thin gauge materials produce a sealing flange that is thin and deforms easily when pressure is applied about the valve cover flange when sealing the gasket to the cylinder head gasket rail. Another deficiency with one piece stamped covers is the time needed to remove and replace valve cover components during periodic inspection or repair. Yet another deficiency for this type of cover is the need to have additional tooling to change the height dimension from short to tall for those situation, such as with some racing engines, that use taller than standard valve train systems. One piece valve covers that are cast from any material suitable for use on an internal combustion engine form a thick rigid cover that is suitable for forming a rigid gasket flange and producing a good seal between the cover and the cylinder head gasket rail, but has the problem of increased weight and cost.
Another deficiency for the one piece cast covers is the same as the stamped one piece cover, i.e., the lack of quick and easy access. Further deficiencies, also present in the stamped version, include the need for additional tooling for a change in dimensions. Casting a two piece valve cover solves the problem of quick and easy access, but still has all the problems of a one piece cast cover plus the addition of added complexity and cost to create a valve cover that is secure and leak resistant when closed.
A primary object of the present invention is to provide a valve cover for easy and quick access to the valve train without the need to remove or replace a valve cover gasket.
Yet another object of this invention is to allow for a two piece design without using the casting method of manufacture, eliminating the need to maintain critical mating dimensions.
Another object of the present invention is to promote improved sealing over prior technologies.
A further object of the present invention is to provide a valve cover of reduced weight and material cost.
Another object of the present invention is to provide a valve cover that can be easily modified for different height requirements without the need for additional tooling cost and inventory.
Yet a further object is to provide a valve cover without the need to have the top cover permanently attached to base flange for sealing and structural rigidity.
In accordance with a preferred embodiment of the present invention, a two piece valve cover for use on an internal combustion engine having an engine cylinder head and a plurality of valve rocker arms, said cover comprises a flexible top portion having an outer rim, the top portion to cover over the rocker arm and cylinder head area of the engine, a separately constructed base flange adapted for sealing engagement to the cylinder head, said base flange having a generally wedge shaped sealing groove portion for guiding and accepting the outer rim of the top portion.
Other objects and advantages of the present invention will become apparent from the following descriptions, taken in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed.